We propose a new steganographic method which is similar to zero-watermarking. In general, digital steganography and digital watermarking, which both embed secret information in host data, have different intended uses. Digital steganography carries embedded secret information through public networks, and the host data serves only as camouflage. Digital watermarking is used to protect host data by embedding secret information. However, the concept of zero-watermarking was proposed in 2001. It does not embed secret information in host data and a result obtained by the interaction of secret information and host data is registered into a certificate authority for protecting the of host data. Our method is also intended to be included in the concept of zero-watermarking broadly. In this paper, we will clarify the difference of zerowatermarking and our method, evaluate the noise immunity of our method, and discuss with various application possibilities.